Various means may be used for obtaining the desired sealing between the ends of the tubes and the sides of the holes in the perforated plate, and may include a sheet of elastomer or the like covering one face of the perforated plate and having collars engaged in the holes therethrough between the ends of the tubes and the sides of said holes. Other means are also provided to prevent axial displacement of the ends of the tubes through the holes in the perforated plate.
While such a heat exchanger is being handled prior to or during its assembly into a vehicle, or after it has been assembled in a vehicle, it may happen in some cases, that there is relative movement between the bundle of tubes and the perforated plate, in particular due to pivoting or to torsion, and especially when the bundle comprises a single row of aligned tubes. These relative movements degrade the sealing between the ends of the tubes and the sides of the holes through the perforated plate, for example by crushing or cutting the collars of elastomer engaged between the ends of the tubes and the sides of the holes, thus giving rise to possible leaks.
Preferred embodiments of the present invention avoid these drawbacks in a simple, cheap and reliable manner.